CT-20 Two-Phase Pressure Drop Method for Tubeside Reflux Condensation

Z. H. Yang and H. Uozu

For some design cases, Xist® 5.0 and previous versions predict unreasonably high two-phase pressure drop for tubeside reflux condensation as the vapor fraction approaches 1.0. Using available experimental data, design cases, and parametric analysis, we reviewed and evaluated the current method. As a result of this study, we developed a new two-phase friction pressure drop method and modified the existing two-phase static pressure drop method for tubeside reflux condensation. Comparisons show that the new method predicts HTRI data within ± 30 percent and greatly improves previous overpredictions of the friction pressure drop at the inlet of reflux condensers, especially for cases with little condensation (weight fraction vapor, y ≈ 1.0) at the tube entrance. Results also show that the modified two-phase static pressure drop method corrects the unreasonable pressure drop profile when y < 0.7.